A balance wheel-hairspring oscillator (10) has a balance wheel shaft (18) intended to be pivotably mounted on a frame of a timepiece. A balance wheel (12) is secured to the balance wheel shaft (18). A hairspring (14) has an inner end (14a) secured to the balance wheel shaft and an outer end (14b) intended to be connected to a connecting member (16) to the frame. A transmission member (20, 22) is arranged to interact with an escapement. The balance wheel (12) and the hairspring (16) are arranged on either side of the transmission member.

A timepiece shaft (1), especially a balance shaft (1), comprising a first functional portion (2a; 2b) including at least one part (221a; 221b) of a pivot-shank (22a; 22b) and/or at least one part (211a; 211b) of a pivot (21a; 21b), the first functional portion being made of ceramic and a first outer diameter (D1) of the first functional portion being less than 0.5 mm, or less than 0.4 mm, or less than 0.2 mm, or less than 0.1 mm.

A timepiece shaft (1), especially a balance shaft (1), comprising a first functional portion (2a; 2b) including at least one part (221a; 221b) of a pivot-shank (22a; 22b) and/or at least one part (211a; 211b) of a pivot (21a; 21b), the first functional portion being made of ceramic and a first outer diameter (D1) of the first functional portion being less than 0.5 mm, or less than 0.4 mm, or less than 0.2 mm, or less than 0.1 mm.

Method for attachment of a last outer coil of a timepiece balance spring inside a groove provided in a balance spring stud, wherein the method includes the step of adhesive bonding the last outer coil of the timepiece balance spring by means of a fluid adhesive whose viscosity is comprised between 200 and 400 mPa.Math.s.

Method for attachment of a last outer coil of a timepiece balance spring inside a groove provided in a balance spring stud, wherein the method includes the step of adhesive bonding the last outer coil of the timepiece balance spring by means of a fluid adhesive whose viscosity is comprised between 200 and 400 mPa.Math.s.

A one-piece balance spring includes a single strip wound on itself between an inner coil and an outer coil. The strip has a geometry such that when the angle of contraction of the balance spring has a value of 360 degrees, there is a constant distance between each coil from the second coil to the penultimate coil.

A one-piece balance spring includes a single strip wound on itself between an inner coil and an outer coil. The strip has a geometry such that when the angle of contraction of the balance spring has a value of 360 degrees, there is a constant distance between each coil from the second coil to the penultimate coil.

A one-piece balance spring including a single strip wound on itself between an inner coil and an outer coil, the strip having a geometry such that when the angle of contraction of the balance spring has a value of 360 degrees, there is a substantially constant distance between each coil from the inner coil to the penultimate coil.

A balance spring includes a strip wound around itself into several coils, the inner coil being integral with a collet including a band extending substantially in the form of a polygon. The outer contour on each bulging portion of the vertices of the polygon includes two axially extending walls substantially parallel to each other relative to the segment formed between the center of the collet and the end of the bulging portion.

A balance spring includes a strip wound around itself into several coils, the inner coil being integral with a collet including a band extending substantially in the form of a polygon. The outer contour on each bulging portion of the vertices of the polygon includes two axially extending walls substantially parallel to each other relative to the segment formed between the center of the collet and the end of the bulging portion.